This circuit operates at a frequency of 80 KHz and modulation up to 60 kHz. The circuit is from 1980s documentation. The PUT is an uncommon component today.
This circuit was found in a 1992 publication, using an operational amplifier not very common...
This is a amplifier for XTAL high impedance earphones or piezoelectric types. Current drain is...
This circuit is from the LM111 manual of the 1980s. The component no longer exists, but...